1. Field of the Invention
The present invention relates to a key device, which is provided to a device such as an electronic device provided with an input means that uses depression of keys, and which detects presence or absence of the depression of the keys, as well as to an electronic device provided with the key device.
2. Related Art
An electronic device such as a cellular telephone device is provided with an input means that uses the depression of keys such as numeric keys. In a conventional input means, the presence or absence of key depression has been detected using an electric circuit formed in matrix state (in lines) (a device for detecting presence or absence of key depression is hereinafter referred to as a “key device”). In other words, in the conventional key device, a particular portion in the electric circuit formed in the matrix state is scanned, and a difference of detecting voltage due to the depression of keys is detected, thereby identifying a depressed key (see, for example, Japanese Unexamined Patent Application, First Publication No. 2003-186607).
However, in the aforementioned input means, switching noise is generated from the electric circuit formed in the matrix state. Accordingly, in the key device, in order to avoid interference by the switching noise, it is necessary to take countermeasures such as appropriately setting a positional relationship between a member, which constitutes an antenna, and an electric conductor such as an electric circuit, and providing a shielding member. In other words, since the design freedom is low in the conventional key device, a key device that makes it possible to enhance the design freedom, as well as an electronic device provided with such a key device have been desired.
Therefore, with regards to a key device, which is provided to a device such as an electronic device including an input means that utilizes key depression, and which detects presence or absence of the key depression, an object of the present invention is to provide a key device that makes it possible to raise the degree of design freedom in the device, and an electronic device including such a key device.